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2 Sheets-Sheet 1.

(No Model.)

W. SCHMIDT. APPARATUS FOR REGULATING SUPERHEATED STEAM. No. 604',547.

Patented May 24,1898.

may.

(No Model.) 2 Sheets-Sheet 2,

W. SCHMIDT. APPARATUS FOR REGULATING SUPERHEATED STEAM. No. 604,547.

Patented May 24,1898.

fa we njar llnrrnn firn'rns Parent @rrrca IVILHELM SCHMIDT, OFBALLENS'IEDT, GERMANY.

APPARATUS FOR REGULATING SUPERHEATED STEAM.

SPECIFICATION forming part of Letters Patent No. 604,5497, dated May 24,1898. Application filed July 17,1896. Serial No. 599,549. (No model.)Patentedin Switzerland June 3, 1896, No. 12,584; in France June22,1896,N0,257,458;i11 Belgium July 2, 1896,1T0. 122,307; in ItalyJuly6, 1896, LXXXII, 324; inHunga'ry July 8, 1896, No. 7,415, and in CanadaNovember 27,1896,N0.54,185-

To all whom it may concern:

Be it known that I, WILHELM SCHMIDT, a subject of the King of Prussia,German Emperor, and a resident of Ballenstedt-on-the- Harz, in the Duchyof Anhalt, German Empire, have invented an Improved Apparatus forRegulating Superheated Steam, (for which patents have been obtained inSwitzerland, No. 12,5Sd, dated June 3, 1896; in France, No. 257,458,dated June 22, 1896; in Belgium, No. 122,807, dated July 2, 1896; inItaly, No. 324, Vol. LXXXII, dated July 6, 1896, in Hungary, No. 7,4:15,dated July 8, 1896, and in Canada, No. 5%,185, dated November 27,1896,)of which the following is an exact specification.

This invention refers in general to steampower plants the engine orengines of which are driven by superheated steam, and in particular toproviding such plants or engines with a device for regulating thetemperature of the superheated steam, said regulating device beingadjustable according to the degree of filling of the cylinder of theengine, or, in other words, the adjustment of said device beingdependent on the degree of filling or on that part of the plant orengine by which the degree of filling of the cylinder is determined. Thepurpose of this arrangement consists in general in regulating thetemper-' ature of the superheated steam, especially the inlettemperature of the same, according to the degree of filling of theengine, and in particular in obtaining by said regulation a practicallyperfect exhaustion of the energy of the superheated steam in such amanner that, first, the greatest part of the work of steam that can berendered at a stroke of the piston is rendered by dry steam, Whereas therest of the Work is rendered by expanding saturated steam, and, second,the steam remains dry at least during the first half of the stroke.

A practically perfect exhaustion of the the oretical energy of the steamin double-acting engines is, as is known, with any of the ordinary modesof employment of the steam not attained, and it is further known thatthe ground of this imperfect exhaustion resides in the loss of heatcaused by the condensation of steam within thecylinder. The means forreducing such loss (furnishing the cylinders with steam-jackets, usingthe steam three or four times in engines With three or four cylinders,and heating the receivers even up to a slight superheating of thereceiversteam) have practically come to a limit already.

The present invention now affords a means of going far beyond that limitof the exhaustion of steam within double-acting engines, said meansconsisting, as already mentioned, in combining the steam-power plant ofthe engine or engines of the same with a device for making the inlettemperature of superheated steam dependent on the degree of filling ofthe cylinder of the engine.

In view of the object of the invention, as aforestated, the regulatingdevice should be able to act in such a manner that on a decrease of thedegree of filling an increase of the inlet temperature takes place, or,reversely, in either case, in such a way that that part of the stroke onwhich the expanding steam remains dry may be of a uniform length inspite of changes in the degree of filling of the respective cylinder. Ifthe regulation of the temperature of the superheated steam is effectedin the manner afore explained, then the expansion of the steam isaccompanied by only a very slight condensation of the latter, becausethe saturated steam arising on the piston traveling through the secondhalf of its path is strongly heated by those parts of the cylinder thathad been heated by the superheated steam during the time in which thepiston performed the first half of its stroke. In fact, no more thanfour per cent. of the steam gets condensed, and the small quantity ofwater of condensation resulting from said four per cent. of steam is,with regard to the whole Work rendered by the steam during a stroke ofthe piston, of so little importance that said quantity of Water ofcondensation maybe practically perfectly neglected. Therefore byproviding the steam-power plant With a regulating device of the kindmentioned there is afforded a possibility of a practically fullexhaustion of the theoretical energy of the steam.

Another advantage resulting from the ar rangement of the regulatingdevice in question or from effecting the regulation according to theprinciple of the present invention consists in the contact-surfaces ofthe cylinder and the piston being perfectly secured against anyinjurious effect of the superheated steam even if this latter besuperheated up to the highest attainable degree. This advantage, whichis far from being insignificant, is a consequence of the great fall oftemperature resulting from the manner of regulation in question. Thisfall of temperature is considerably greater than can be attained withthe use of saturated steam of the same tension, and in spite of the useof highly-superheated steam that part of the cylinder which thepacking-rings of the piston pass through assumes a medium temperature ofsuch a degree that this, part as well as the packing-rings are perfectlysecured against any deleterious influence of the heat of the steam. Thisis the case in the highest attainable degree, especially if the pistonreceives a greater length than has been customary up to now and if thelength of the cylinder, too, is correspondingly increased. I have foundit advantageous to let the piston have a length of at least thirty percent. of the length of the way which the piston is traveling through;but this minimum of length should be employed only if a piston andcylinder of a greater length cannot be used for want of space or if oneis satisfied with the expanding superheated steam remaining dry only forforty per cent. of the whole length of the way of the piston. If,namely, this steam is to remain dry considerably beyond the middle ofthe stroke, then the inlet temperature must be greatly increased. Theemployment of the superheated steam is made unnecessarily difiicult anda corresponding increase (corresponding to the higher inlet temperature)in the exhaustion of the energy of the steam is not obtained.

fected in such a way that the superheated steam turns into saturatedsteam already considerably before the piston has finished the the energyof the steam is greatly reduced, because the proportionately greatestcondensation of the steam occurs during the first half of the stroke.Therefore the device for regulating the temperature of the steam must(with regard to the degree of filling of the cylinder with that steam)be able to be adjusted in such a manner that the steam does not remaindry considerably beyond the middle of the piston-Way and does not getsaturated considerably before said middle, and, further, the cylinder(after the degree of filling by which the adjustment in question iseffected) should have such a length that the packing-rings of thecorrespondingly longer piston move mainly in that zone of the cylinderin which the steam has got saturated already.

In the preceding paragraphs it had been mentioned already that theregulating device for the temperature of the steam could be combinedeither with the boiler of the steampower plant or with the engine of thesame. In the first of these cases the regulation (according to thedegree of filling) would thus be effected directly in the generator forthe superheated steam, whereas in the other case the regulation iseffected by removing from the superheated steam the respective excess ofheat before the steam enters the cylinder of the engine. Of course thisremoval of heat will in any case be effected in the useful way forinstance, by transmitting the excess of heat to steam having atemperature lower than that requisite with regard to the degree offilling of the cylinder. Generally this steam will be saturated steam,and the regulation of the inlet temperature may thus be effected bymixing the too-highly-superheated steam with as much saturated steam asis necessary for bringing about such a course of work of the steamwithin the cylinder as corresponds I to the principle of the presentinvention. This admixture of saturated steam to the superheated steam orthe corresponding ad j ustment of the respective valve may well beeffected in an automatic manner.

There may be employed, for instance, an automatic valve 'the movementsof which are dependent on the tension of the steam present within orflowing into the cylinder, or the valve may be actuated compulsorily byconnecting it to the governor or to the steam-distributing device of theengine, or the steam-distributing valve itself may be so constructed asto be able to workaccording to the idea of invention. Finally, theuseful removal of the excess of heat may be effected not solely by steamof a lower temperature, but also by Waterfor instance, byfeed-water-which then is preliminarily heated by the said excess ofheat. If, 011 the other hand, the regulation is ef- 1 In order to makemy invention more clear,

I refer to the accompanying drawings, in g which similar letters denotesimilar parts throughout the different views and in whichfirst half ofits stroke, then the exhaustionof Figure 1 shows a vertical sectionthrough a generator for superheated steam, together with some parts ofan engine intended to be driven by such steam and together with themechanisms for regulating the inlet temperature of the superheated steamaccording to the principle of the present invention. Fig. 2 is an outerview of the steam-generator shown in Fig. 1, the mechanism for effectingthe said regulation being, however, another one. Fig. 3 is a verticallongitudinal section through the valve 2' of Fig. 2 and being drawn on alarger scale, and Fig. 4 is a longitudinal section through a particularconstruction of a steam-distributing valve and through the adjacentportions. of the cylinder having that valve. I

Referring to Fig. 1, his a pipe that connects the steam-space of theboiler proper, A,

with the steam-inlet pipe 13 for the cylinder 0. The pipe Bis connectedto one end of the superheater D, the other end of which is connectedwith the steam-space aforementioned by means of .the pipe E. The pipe his furnished with a valve g, that is connected to the lever F of theregulator G by means of the rod II. Supposing the regulator be caused toact in such a manner as to cause in its turn an increase of the degreeof filling, the valve Q will be opened in a corresponding degree, so asto allow of a certain quantity of wet steam to pass over into the pipe Band to mix with the superheated steam flowing through said pipe. Thetemperatureof the superheated steam is therefore reduced in a measurecorresponding to the increased degree of filling. If, on the other hand,the degree of filling is reduced, the regulator acts upon the valve ginthe reverse way-2'. 6., closes said valve either nearly or wholly.

In the form of construction shown in Figs. 2 and 3 the variations ofpressure caused within the pipes B and h by the influence of theregulator in question are made use of. For this purpose the pipe hisfurnished with an automatic valve 2, the valve proper, t, of which issuspended by a spring i The tension of said spring is so chosen that thepressure of the wet steam (within the boiler proper, A) is notsufficient to open the valve proper, 2'. If, however, the pressurewithin the pipe B get-s reduced in consequence of a sudden increase inthe degree of filling of the cylinder 0, the valve proper, t, is raisedby the wet steam and a certain quantity of the latter passes through thepipe h into the pipe B. The temperature of the superheated steam passingthrough the pipe B into the cylinder is therefore reduced in a measurecorresponding to the increased degree of filling.

Another construction for admixing wet steam with the superheated steamis represented in Fig. 4, in which 7c is the inlet for the superheatedsteam and Z the inlet for the wet steam. The ports J J, through whichthe superheated steam passes into the cylinder or to one or the otherside of the piston, respectively, are opened and closed by the endportions K K of the piston-valve K The annular port J through which thewet steam may pass over from the aperture Z into the valve-casing, iscontrolled by the portion K of the piston-valve. The extent of motion ofsaid portion K of the piston-valve is controlled by the regulator,according to the degree of filling of the cylinder. If the degree offilling is but small, the port J 2 will not be opened at all, whereas itis automatically opened if a greater degree of filling is required. Ofcourse the piston-valve K should be connected either to a link motion orto a fiy-wheel regulator, so that the extent of motion of said valve maybe made dependent on the degree of filling of the cylinder, asaforedescribed.

Having thus fully described the nature of this invention, what I desireto secure by Letters Patent of the United States is- 1. The combinationwith a generator for superheated steam, and with an engine adapted to bedriven by such steam, of a regulator for the temperature of that steam;said regulator being adapted to be automatically adjusted according tothe degree of filling of the cylinder of said engine, for the purpose asdescribed.

2. The combination with a generator for superheated steam, and with anengine adapted to be driven by such steam, of a regulator for thetemperature of said steam; said regulator being connected to the meansthat determine the degree of filling of the cylinder of said engine, forthe purpose as described.

3. The combination with a steam-generator, a superheater for the steam,an engine adapted to be driven by the superheated steam and a connectionbetween said superheater and said engine, of a connection between thelatter and said generator so as to allow of the admixing ofnon-superheated steam to the superheated one, and a steam-distributingdevice adapted to control said admixing and connected to the means thatdetermine the degree of filling of the cylinder of the said engine, forthe purpose as described.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

WILHELM SCHMIDT. Witnesses:

W. HAUPT, R. HERPIOH.

